Chemistry Lasers Identify Pigments in Medieval Manuscripts

February 13, 2025

a laser beams into a 16th century manuscript as part of the raman spectroscopy process

How Raman Spectroscopy Helps Tell A Bigger Story

In partnership with Rauner Special Collections Library - and with the help and expertise of Instrument Core Facility Manager Paul Defino and Instrument Specialist Chris Snyder of the Chemistry Department - senior lecturer Jenny Lynn is embarking on an exciting scholarly investigation. Jenny arranged for Paul and Chris to co-conduct multiple experiments to identify pigments (and so their compounds) in several of Rauner Library's pre-1600 manuscript fragments using Raman spectroscopy. This technique uses a source of monochromatic light, usually a laser, to determine a sample's molecular makeup.

I’m so grateful to Paul and Chris for their patience and skill, and for having access to the Instrument Core Facility. I knew what I wanted to be able to do, but it wasn’t until I found them that I had a way to do it.

Jenny Lynn

Why does it matter to know the pigment compounds? Much like a unique fingerprint, the composition of pigments tells a story about their geographical origins, the workshop where they were used, and potentially the maker of that particular part of a manuscript. For example, a Book of Hours can be bound, then reworked, repaired, and have pages removed or added throughout its life, passing from one owner to another. Each change comes with its own history, its own story. Qualifying the varying pigments and their compounds helps researchers understand the narrative behind a book or manuscript’s making.

While watching a particular wave pattern reveal itself on the desktop screen, Chris identified that it correlated to the color vermilion, a red-orange. Vermilion was commonly used from antiquity until the 19th century. It was extracted from the highly poisonous mineral cinnabar, containing both sulfur and mercury. Jenny was excited about the finding. Not because she didn't guess it was vermilion, but because the test result proved that using Raman spectroscopy on these manuscripts works.

results from the raman spectroscopy laser into a pigment and the resulting wave lengths

The outcomes of these tests mean Jenny can introduce another layer of learning and knowledge discovery to her Latin Paleography students, who will meet at Rauner Library during the upcoming Spring Term. They’ll receive loose manuscript pages to transcribe, translate, and place under the laser to garner a bit of the history behind the page.

Cutting-edge research and discovery have been fueled by close collaboration between the sciences and the humanities since at least the beginning of the Scientific Revolution in the 1500s. This project is such a cool example of this dynamic in action.

Morgan Swan, Rauner Library

Though this approach is new for analyzing illuminated manuscript pigments here at Dartmouth, there are many precedents for this sort of non-invasive experiment. Almost a decade ago, the University of Durham, a fellow member of the Matariki Network, conducted a large-scale project using Raman spectroscopy and then presented their findings.

Morgan Swan, Special Collections Librarian for Teaching and Scholarly Engagement, is thrilled by this project: “Cutting-edge research and discovery have been fueled by close collaboration between the sciences and the humanities since at least the beginning of the Scientific Revolution in the 1500s. This project is such a cool example of this dynamic in action, and I love that students will be amplifying Dartmouth’s impact across the scholarly ecosystem even while they are unlocking their own individual potential by practicing advanced research skills.”

Chris shares that though the Instrument Core Facility primarily serves the Chemistry Department, “we have students from Thayer and Geisel who use our facility regularly, and we welcome users from across Dartmouth who wish to use our instruments to analyze samples.”

We couldn’t be more curious and excited about coupling scientific techniques such as Raman spectroscopy with the humanities in innovative ways, and what results for researchers and their scholarship. With Jenny's spring term class (and her work with a French Book of Hours) intending to use this technology, we imagine there will be much to discover!

Curious how Rauner Library might be a partner in your research and teaching?

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